(a) Field of the Invention
The present invention relates to a method and apparatus for managing synchronization groups in a wireless communication system. More particularly, the present invention relates to a method and apparatus for managing synchronization groups which can reduce interference between different synchronization groups in a wireless communication system, such as a wireless mesh network or a mobile ad-hoc network.
(b) Description of the Related Art
802.11 Wireless Local Area Network (WLAN) technology is representative conventional wireless ad-hoc network technology. In 802.11 wireless local area network (WLAN) technology, each node in Distributed Coordination Function (DCF) mode uses a distributed access method. The distributed access method in 802.11 DCF mode is performed based on Carrier Sense Multiple Access (CSMA), and each node sends its own data according to CSMA when adjacent nodes do not send their data.
In 802.11 DCF mode, although two different networks neighbor each other, each of the nodes of the two groups can recognize the transmission of the node of the counterpart group according to CSMA and send its own data when the node of the counterpart group does not send its data.
Each node in wireless technology in which a TDMA-based frame not using CSMA, such as 802.11 Point Coordination Function (PCF) mode and 802.15.4 Guaranteed Time Slot (GTS) duration, is used, attempts to send and receive data in a slot allocated thereto. Here, the slot is allocated by taking only a node belonging to the same network into consideration. Accordingly, if an adjacent network is present, it can affect interference between groups if data is attempted to be transmitted in the allocated slot.
Furthermore, in order to determine whether or not an adjacent network is present, a broadcasting message has to be received from a node in the adjacent network. If a TDMA frame start time is different in each network, it is difficult to determine whether or not an adjacent network is present because a time during which the broadcasting message is received is different.
That is, in existing wireless technology in which a TDMA-based frame is used, there is a problem in that interference from different networks continues.